Discussion
Home ‣ Aptitude ‣ Volume and Surface Area Comments
- Question
- What is volume of a cone having a base of radius 10 cm and height 21 cm?
Options- A. 2200 cm3
- B. 3000 cm3
- C. 5600 cm3
- D. 6600 cm3
- Correct Answer
- 2200 cm3
ExplanationVolume of cone = (1/3)?r2h
= (1/3) x (22/7) x 10 x 10 x 21 = 2200 cm3 - 1. The diameter if base of a right circular cone is 7 cm and height is 10 cm , then what is its lateral surface area?
Options- A. 110 sq cm
- B. 100 sq cm
- C. 70 sq cm
- D. 49 sq cm Discuss
- 2. The curved surface area of a right circular cone of radius 14 cm is 440 sq cm. what is the slant height of the cone?
Options- A. 10 cm
- B. 11 cm
- C. 12 cm
- D. 13 cm Discuss
- 3. A pillar 14 cm in diameters is 5 m high. How much material was used to construct it?
Options- A. (77 x 102)cm3
- B. (77 x 104)cm3
- C. (77 x 105)cm3
- D. (77 x 103)cm3 Discuss
- 4. A cylindrical pillar is 50 cm in diameter and 3.5 m in height. Find the cost of painting the covered surface of the pillar at the rate ? 10 per sq m .?
Options- A. ? 50
- B. ? 68
- C. ? 98
- D. ? 55 Discuss
- 5. The diameter of a roller is 84 cm and its length 120 cm. Its takes 500 complete revolutions to move once over to level a playground (in sq m)?
Options- A. 1632
- B. 1817
- C. 1532
- D. 1584 Discuss
- 6. The diameter of the base of a cone is 6 cm and altitude is 4 cm, What is the approximate curved surface area of the cone?
Options- A. 45 cm2
- B. 47 cm2
- C. 49 cm2
- D. 51 cm2 Discuss
- 7. The volume of a right circular cone is 100? cm 3 and its height is 12 cm. Find its slant height.?
Options- A. 13 cm
- B. 16 cm
- C. 9 cm
- D. 26 cm Discuss
- 8. If the volume of a right circular cone of height 9 cm is 48? cm 3, then find the diameter of its base.?
Options- A. 8 cm
- B. 4 cm
- C. 7 cm
- D. 11 cm Discuss
- 9. Shantanu's cap is in the form of a right circular cone of base radius 7 cm and height 24 cm. Find the area of the sheet required to make 5 such caps.?
Options- A. 5000 sq cm
- B. 2750 sq cm
- C. 3000 sq cm
- D. 2700 sq cm Discuss
- 10. The radius of the base of a right circular cone is doubled. To keep the volume fixed, the height of the come will be?
Options- A. half of the previous height
- B. one-third of the previous height
- C. one-fourth of the previous height
- D. 1/?2 times of the previous height Discuss
Volume and Surface Area problems
Search Results
Correct Answer: 110 sq cm
Explanation:
Given that,
Diameter of a right circular cone = 7 cm
? Radius of a right circular cone = 7/2 cm
and slant height of a right circular cone (l) = 10 cm
? Lateral surface area of a cone = ?rl = (22/7) x (7/2) x 10
= 11 x 10 = 110 cm2
Correct Answer: 10 cm
Explanation:
Curved surface area of right circular cone = ?rl
? 440 = (22/7) x 14 x l
? l = (440 x 7) / (22 x 14) = 10 cm
Correct Answer: (77 x 103)cm3
Explanation:
Volume of the cylinder = ?r2h
= (22/7) x 7 x 7 x 500 = 77000
= (77 x 103) cm3
Correct Answer: ? 55
Explanation:
Curved surface area = 2?rh
= 2 x (22/7) x 0.25 x 3.5
= 5.5 sq m
? Cost of painting 5.5 sq m = 10 x 5.5
= ? 55
Correct Answer: 1584
Explanation:
In one revolution, area covered = Covered surface area
? 2?rh = 2 x (22/7) x 42 x 120 = 31680 sq cm
in 500 revolutions,
Area covered = 31680 x 500 = (1584 x 104) sq cm
= (1584 x 104) / (104) = 1584 sq m
Correct Answer: 47 cm2
Explanation:
Radius of cone (r) = 6/2 = 3 cm
and height of cone (h) = 4cm
Slant height (l) = ?h2 + r2
= ?(4)2 + (3)2
= ?16 + 9
= 5 cm
Now, curved surface area = ?rl
= (22/7) x 3 x 5
= 330/7 = 47 cm2
Correct Answer: 13 cm
Explanation:
Volume = (1/3)?r2h
According to the question,
(1/3)?r2h = 100?
? (1/3)?r2 x 12 = 100?
? r2 = 25
? r = ?25 = 5 cm
? Slant height (l) = ?h2 + r2
= ?122 + 52
= ?169 = 13 cm
Correct Answer: 8 cm
Explanation:
volume = 48 ? cm3 and h = 9 cm
? (1/3)?r2h = 48?
? (1/3) x ? x r2 x 9 = 48?
? r2 = (48? x 3) / (? x 9) = 16
? r = ?16 = 4 cm
? Diameter = 2r = 2 x 4 = 8 cm
Correct Answer: 2750 sq cm
Explanation:
Slant height (l) = ?r2 + h2
=?72 + 242
= ?49 + 576
= ?625
= 25 cm
Curved surface area = ?rl = (22/7) x 7 x 25 = 550 sq cm
? Area of 5 caps = 550 x 5 = 2750 sq cm
Correct Answer: one-fourth of the previous height
Explanation:
In first situation.
Radius = r1, height = h1 and volume = v1
In second situation,
Radius =2r1, height = h2 and volume = v2
In the volume is fixed, then
v1 = v2
? (1/3)?r21h1 = (1/3)?(2r1)2h2
? h1 = 4h2
? h2 = h1/4
Therefore, height of the the cone will be one-fourth of the previous height.
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